CSS grid

<main>
  <div class="h2 w2"></div>
  <div></div>
  <div></div>
  <div class="h2"></div>
  <div class="h2 w2"></div>
</main>

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
body {
  background-color: blue;
  height: 100vh;
}
main {
  display: grid;
  height: 100%;
  grid-template-columns: 1fr 1fr 1fr;
  grid-template-rows: 1fr 1fr 1fr 1fr;
  padding: 0.5rem;
  gap: 0.5rem;
  align-items: stretch;
}
div {
  background-color: yellow;
  border-radius: 2rem;
}
.w2 {
  grid-column-end: span 2;
}
.h2 {
  grid-row-end: span 2;
}